Of interest is commonly owned copending application Ser. No. 644,712 entitled "Sensor Matrix" by the present inventor and filed concurrently herewith.
A device of this kind is known from European Patent Specification 0 028 960 which corresponds to U.S. Pat. No. 4,382,187. In the known device the charges of the sensors of a row are simultaneously read. To this end, there is provided a circuit for the sensors which activates the electric switches of the sensors so that their charges can be output via a read line provided for each column. The charges of a row are thus simultaneously read, i.e. in parallel. The charges thus read in parallel are applied to transfer means which convert the parallel signals into a serial signal. To this end, according to the cited European Patent Specification a common multiplexer or a common shift register is therefore provided for all read lines.
Notably for X-ray applications only very small X-ray doses are incident on the sensors. Consequently, the electric charge generated in the sensor elements in dependence on the amount of incident of radiation, is also very small. Due to these very small charges to be read, problems are often encountered, i.e. a comparatively strong noise is superposed on the signal read. In order to counteract this problem, the cited European Patent Specification proposes a respective amplifier for each sensor. This amplifier amplifies the charges generated in the sensor, the charges subsequently being readable in amplified form, via an electric switch and the associated read line.